This invention relates to the field of textile or material fabrication and processing; in particular to an apparatus and method for reciprocation of one or more needles for such fabrication and processing purposes, particularly for tufting, needling and sewing purposes.
Tufting, needling and sewing are well known processes which are characterised by the reciprocating use of at least one needle for the purpose of making or processing textiles or related materials. Tufting is a method of inserting, with needles, pile yarn into pre-made substrates. Carpets and bed coverings are examples of products commonly obtained by such processing. Needling is a process whereby battingxe2x80x94layers of non-woven fibresxe2x80x94are pierced with barbed needles to produce, for example, needled felts or needled floor covering fabrics. Machine sewing comprises a system of combined loop movements which involve reciprocation of a yarn transporting needle.
Prior art tufting, needling and sewing systems generally employ mechanical. components such as cam discs, tension rollers, crank actuating systems, etc. These systems are of relatively low efficiency, requiring high energy input, and in use have large inertias. Furthermore, it is at best difficult to vary working parameters such as pattern and stitch length with these prior art systemsxe2x80x94certainly on rapid timescales, e.g. on a stitch by stitch basis. U.S. Pat. Nos. 3,735,717 and 3,875,489 describe an electromagnetic drive system which may be applied to sewing machines to provide synchronised motion of needle and bobbin carrier. These documents represent an earlyxe2x80x94possibly seminalxe2x80x94attempt to move away from traditional mechanical components.
The present invention addresses the aforementioned problems, and, further, provides textile fabrication and processing systems that can react rapidly and adaptively to changes in working conditions.
According to one aspect of the invention there is provided a material or fabric making or processing operation involving needle penetration of a fibre, fabric or material layer in which the needle penetration action is controlled by control means by which the needle penetration characteristics can be varied within the penetration action and as between penetration actions.
The needle penetration characteristics may comprise stitch or loop height, stroke, stroke frequency, pitch length or combinations thereof. It should be noted that the stitch or loop height may differ from the strokexe2x80x94which is a measure of the mechanical movement of the needlexe2x80x94because of yarn tension and relaxation effects in surrounding stitches.
It will be understood that the needle penetration action includes the withdrawal of the needle from the material or fabric, and that this withdrawal is also controlled by the control means.
The needle penetration action may be controlled by a feedback arrangement wherein at least one variable is sensed and in response to said at least one variable the needle penetration characteristics and/or other apparatus characteristics are adjusted so as to optimise or counteract variations in a defined operational characteristic or characteristics. Consequently, optimised dynamic elements such as control, power, production rate, patterning format, system deviations are monitored and controlled, or used under total control as a teach mode facility.
The control means may comprise at least one electronically controlled servo actuator. Such actuators are employed in place of the high energy, low efficiency mechanical systems traditionally used, which systems may comprise cam discs, tension rollers, lay shafts, eccentrics and crank actuating systems. The electronically controlled actuators are low energy, high efficiency devices which can achieve higher operating speeds than traditional mechanical systems. The control means may further comprise a microprocessor or computer.
The variables sensed may include actuator position and actuator force profile.
Yarn tension may be sensed.
The actuator or actuators may comprise linear actuators.
The actuator or actuators may comprise rotary actuators.
At least one secondary operation may be controlled by the control means.
At least one secondary operation may be controlled by a master-slave system.
The operation may be tufting and the secondary operation may comprise looping, and may further comprise cutting.
The operation may be sewing and the secondary operation may comprise stitch locking.
The operation may be needling and the secondary operation may comprise translation of batting. The at least one secondary operation may further comprise upward motion of a base plate and a stripper plate by at least one actuator, said motion acting to increase the relative velocity of the plurality of needling needles with respect to the base plate and stripper plate.
The operation may be a needling operation for fabricating a three dimensional felted structure comprising the steps of:
mounting a three dimensional non-woven material substrate; and
needling said substrate with at least one needle board having a plurality of needles; said needling being accompanied by relative movement or rotation of said substrate and said needles.
Two needling boards or sets of needling boards may be employed, said boards or sets of boards reciprocating along mutually orthogonal axes.
The three dimensional structure thus produced may be set by plastifying, coating or heating.
The three dimensional substrate may be produced from a pre-needled, carded felt. The pre-needled, carded felt may be divided into sections and reassembled to produce the three dimensional substrate.
According to a second aspect of the invention there is provided apparatus for material or fabric making or processing comprising at least one fibre, fabric or material layer penetrating needle, and control means for controlling the needle penetration action such that the needle penetration characteristics can be varied within the penetration action and as between penetration actions. The control means may comprise at least one electronically controlled servo actuator.
The actuator or actuators may comprise linear actuators.
The actuator or actuators may comprise rotary actuators, and said rotary actuators may produce linear or arcuate reciprocation of the needle or needles through a rotary to linear converter or a rotary to arcuate converter.
The control means may firer comprise a microprocessor or computer.
The control means may comprise at least one sensing means for sensing a variable and the control means may adjust the needle penetration characteristics and/or other apparatus characteristics in response to said variable or variables so as to optimise or counteract variations in a defined operational characteristic or characteristics. The sensing means may comprise actuator position monitoring means, actuator force measurement means, yarn tension monitoring means, or combinations thereof. Other parameters, such as temperature and humidity, may be sensed.